Single position clutch



Patented Oct. 24, 1944 2,361,360 SINGLE POSITION CLUTCH Hugh C. Ressler, West Brighton, N. Y. n

Application March 11, 1942, Serial No. 434,192 1 7 3 Claims.

The present invention concerns clutches and, in particular, a single position clutch suitable for facsimile scanner drums and the like.

One object of the present invention is to provide an improved clutch mechanism capable of especially smooth operation.

Another object is to provide an improved clutch mechanism which operates smoothly and yet enages automatically.

Still another object is to provide an improved clutch mechanism which engages only in a fixed position and still without jolting at any point from rest to full speed- A further object is to provide an improved clutch mechanism having the above characteristics, together with a simplified operating or disengaging mechanism. a

A still further object is to provide a single position clutch which is mechanically balanced.

These and other objects will be evident from the detailed description of the invention given in connection with the various figures of the drawing.

In the past there have been two general types of clutches. One type of clutch is one which provides a gradually increasing friction in starting a mechanism and which finally engages fully. but in a random position. The other type of clutch is one in which a key drops into a slot giving sudden engagement, but in a fixed'position. In facsimile it is desirable to provide a clutch which provides fixed relation between the driving and the driven parts upon full engagement but one which engages smoothly. The clutch which is the subject of the present invention provides this gradual action and final fixed relationship. The fixed relationship is required in facsimile, so that in a synchronously operating system the scanner drum may be stopped and started without losing the phase condition of the system. The clutch should operate gradually so that the equipment is not thrown out of phase or unduly Jarred by the stopping and starting of the drum.

In the drawing: v

Fig. 1 shows a cross-section of one form of the present invention.

Fig. 2 shows a detail of the construction of Fig. 1.

Figs. 3 and 4 show additional details ofthe construction of Fig. 1.

Fig. 5 shows a. greatly enlarged detail of a part of Fig. 1.

Fig. 6 shows the relation of the present invention to a complete facsimile scanner.

In Fig. 1 is shown a cross-section of one form of clutch, in accordance with the present invention. A facsimile drum I, is supported by end piece 2 and clutch parts 8 and I upon shaft 4, and is free to turn thereon. Shaft 4 is turned down at its ends toform bearings 5 and 6. Inside drum I is fitted the outer part of the clutch I. This outer part of the clutch I contains a round opening carrying grooves l4 and I5 and the round holes I8 and I9. Fitting into part I is the inner part of the clutch B which is keyed to shaft t by means of key 9 passing thru keyway I0 and operating pin II. Keyway I0 is elongated along the length of shaft 4, so that the inner part of the .clutch 8 may slide back and forth along shaft 6.

Projecting slightly from the surface of part 8 are ball bearing balls I6 and I1 (Fig. 2) spaced in the direction of axis 4 by the same amount as grooves It and I5 and holes I8 and I9. v Pressing a ainst key 9 is spring I2 held in well I3 in shaft t. Opposite spring I2, shaft 6 is hollow and'fitted with the clutch operating pin I I. 7

As is shownin the detail drawing of Figs. 3 and 4 balls I6 and- I I are pressed ina substantially radial direction. by springs 2| and'23 fitting in holes 20 and 22. Balls IS and I! are prevented from falling out of holes 20 and 22 by narrowing the outer ends of holes 20 and 22 slightly as shown in detail at 20 in Fig. 5.

In operation, pin II is pushed inward to disengage the clutch and is allowed to move outward to engage the clutch. Shaft 4 is turned by suitable means and whenthe clutch is engaged, drum I is tied to shaft 4 and turns at the same speed.

When the clutch is disengaged, drum I is freed from shaft 4 and may be held still for the purpose of attaching copy to it.

The clutch is disengaged by pushing pin II inward by means of rod 31 acting thruball 36. Rod

31 is actuated by pushing in on knob 39 and tuming it so that flange 38 passes over raised portion tl on mounting 40. This moves the inner clutch part 8 by means of key 9 and against spring I2 until the relative positions of parts i and 8, shown in Fig. 4, is assumed. In this condition, ball II rides freely in groove I5, ball I6 rides freely in groove It and drum I is freed from the turning influence of shaft 6.

To engage the clutch, pin II is released and part 8 movm along shaft t until parts land 8 are in, the relative positions shown in Fig. 3. Ball I! is thenopposite holeIQ and ball I8 is opposite hole I8. As shaft 4 and hence part 8 rotates while drum I and part I stand still, balls J6 and I! drop momentarily into holes I8 and I8 at each revolution, imparting a turning impulse -todruml.

ner in which holes 20 V I9 to clutch part I.-

.simile pick-up scanner.

springs ZI and 23, may

This slight turning impulse gradually starts drum I to turning and at an increasing speed. Finally, drum I is speededup to the same speed as shaft 4 and balls I8 and I1 drop into holes I8 and I9 and stay there, looking drum I to shaft l. and the tension of springs 2| and 23 are chosen so that drum I is brought up to speed by a series of slight impulses and finally locked to shaft 4. This provides a smoothly starting drum free from large sudden shocks which might be reflected in the driving motor and result in loss of synchronization or at least the initial phasing of the motor. While this clutch starts the drum smoothly. it finally assumes a single position, whereby drum l and shaft 4 are in a predetermined relative position. Thus drum I may be stopped and restarted phase position with respect to the driving motor. In synchronized systems it is important to be able to stop and start drum phase relations in the system, for instance, in order to change the copy being transmitted.

In Fig. 2 is showna cross-section taken along line 12 in Fig. 1. It shows in detail the manand 22 pass thru clutch relation of holes I8 and It also shows the relative positions of balls I6 and I1, pins 8 and II and springs 2| and 23. j

While not intended to limit the applications Of the clutch, Fig. 6 shows it applied to a fac- Drum l is shown with part 8. It shows the shaft 4 projecting. Bearings mountings 28 and 24 are shown. Rod 31, knob 38 and mounting 40 are shown. A driving motor 28 drives shaft 4 thru a suitable gear'box 21. Motor 28, ear box 21, bearings 24 and 26 and mounting Ml are carried by bed plate 25. Copy to be scanned is carried on the surface of drum I.v The scanning is carried out by means of a lamp 29 iocussed to a fine spot by lens 3i and the light reflected by the copy on drum I is iocussed on photo-electric cell 30 by means of lens 32. Signals generated by photo-electric cell 80 are amplified by'amplifier 33 and are passed to a utilization means over wires 34 and II. r

It is obvious that balls I8 and Il, together with be interchanged with holes I8 and I9 and grooves I4 and I placed on part 8 without aflecting the operation of the V clutch.

While one embodiment and one application of the clutch which is the subject of the present The dimensions of the various parts 5 and 5 carried by invention have been shown and described, many modifications and other applications will be apparent to those skilled in the art within the spirit and scope of the invention as set forth in the appended claims.

What is claimed is:

l. A single position clutch including in combination, a drive shaft, a driving member keyed to said shaft and carrying a' steel ball urged in a substantially radial direction by means of a spring, a member to be driven concentric with said driving member and including a concentric groove for allowing free passage of said ball and an opening for detaining said ball, means for and drum I will'always be in the same I without changing the moving said driving member to a position where said ball rides ireely in said groove thereby disengaging said clutch, and a'spring for moving said driving member to a position where said ball strikes said opening for engaging said clutch with a predetermined relative position of said driving member and said member to be driven.

2. A single position clutch including in combination, two concentric members, one of said members being a driving member and the other a driven member, at least two detent devices substantially equally spaced circumferentlally around one of said members and carried by the last said member at diiferent axial positions, and means for urging said detent devices into openings in the other of said members corresponding in number and position to said detent devices for transmitting torque from said driving member to said driven member at unique angular positions of said members with respect to each other.

3. A single position clutch including in combination, two concentric'members, one of said members being a. driving member and the other a driven member, at least two smoothly rounded detent devices'substantially equally spaced circumferentially around one of said members and carried by the last said member at different axial I provide an'idling condition.

HUGH C. RESSLEB. 

